The first week of August is a big one in baseball. It kicks off the stretch run in earnest, as the standings take shape and the playoff implications for games become clearer.

Rivalry matchups start to mean a little more. Winning and losing streaks have a more decisive impact on the status of October hopefuls. And with the Trade Deadline in the past, contenders' key acquisitions are starting to make a big impact for their new clubs in the playoff push -- and in the MLB.com Power Rankings.

Kris Bryant is raking for his new club, the Giants, who continue to set the pace not just for the National League, but the Major Leagues. But the rival Dodgers are already getting superstar performances from Max Scherzer and Trea Turner, and they're putting the pressure on San Francisco in the NL West. The NL East race is also wide open, as the Phillies leapfrogged the scuffling Mets this week.

In the American League, the Rays and their own big trade acquisition, Nelson Cruz, are slugging their way back to the top of their division. The other two division leaders, the White Sox and Astros, are holding onto the top spots they've held for a while. But the AL Wild Card race is really heating up.

The Red Sox have faltered, and the Yankees, Blue Jays and A's are all playing strong baseball. New York and Toronto both had five-game win streaks this week, and the A's week included back-to-back walk-off wins against the Padres and Rangers. All four clubs -- Boston, Oakland, New York and Toronto -- are within three games of each other for the two Wild Card spots.

With all that in mind, here are this week's Power Rankings:

Biggest jump: The Phillies jumped up five spots, from 16 to 11, thanks to an undefeated week. Philadelphia is on an eight-game win streak and capped off the week by sweeping the rival Mets to take over first place in the NL East. The Mets had been in sole possession of first since May 9 until the Phillies took over with their win in Friday's series opener.

Biggest drop: The Mets and Blue Jays both fell three spots; the Mets from 10 to 13 and the Blue Jays from 11 to 14. In New York's case, that's what happens when you lose the division lead you've held for several months and fall into third place (the Mets now trail the Braves, too). Toronto's week was good, though -- the Jays won five straight and then finished with an epic comeback win against the Red Sox on Sunday, capped by George Springer's go-ahead three-run homer. It's just that other teams near them in the rankings are also hot, like the Phillies, Reds and Yankees.

Power Rankings Top 5

1) Giants (2 last week)
Even with the Dodgers adding Scherzer and Turner at the Trade Deadline, the Giants and their own new star, Bryant, remain the surprise powerhouse of the NL West. They became the first team in baseball to reach 70 wins this week and are 30 games over .500. After Bryant homered in his first game with San Francisco last Sunday, he added a pair of three-hit performances this week.

2) Dodgers (1)
Mad Max was dominant in his first game in an L.A. uniform -- Scherzer beat the AL West-leading Astros with seven innings of two-run, 10-strikeout baseball in his debut at Dodger Stadium. Turner made his Dodgers debut, too, and the speedster also stole his first base with his new team Saturday, bringing his total to 22 for the season. The Dodgers trail the Giants in the division, but have a firm grip on the top NL Wild Card spot.

3) Astros (3)
The Astros didn't make a blockbuster trade at the Deadline, but they're maintaining the lead in the AL West that they've held since June 21. The A's are close to Houston in the standings, but the Astros have a much better run differential -- they're outscoring their opponents by nearly 100 more runs than Oakland this season.

4) White Sox (4)
The AL Central leaders continue to look strong, and they have the benefit of a very comfortable lead in their division over the Indians. The White Sox clinched an early series win against the crosstown rival Cubs over the weekend, with newly acquired second baseman Cesar Hernandez hitting a big home run Friday and breakout ace Carlos Rodón pitching an 11-strikeout gem Saturday.

5) Rays (5)
The reigning AL pennant winners reclaimed the lead in the AL East last week and expanded it this week. The Rays ended the week on a four-game winning streak, a run that included big games from Cruz on Friday and Saturday (home runs in both games and seven total RBIs) and a dramatic comeback Sunday with Brett Phillips belting a tiebreaking grand slam in the eighth inning of Tampa Bay's series finale against the Orioles.

The rest of the field of 30

6. Brewers (7 last week)
7. Padres (8)
8. Red Sox (6)
9. Yankees (12)
10. A's (9)
11. Phillies (16)
12. Reds (13)
13. Mets (10)
14. Blue Jays (11)
15. Braves (15)
16. Mariners (14)
17. Cardinals (18)
18. Indians (17)
19. Tigers (20)
20. Angels (19)
21. Marlins (21)
22. Twins (22)
23. Nationals (24)
24. Cubs (23)
25. Rockies (26)
26. Royals (25)
27. Orioles (27)
28. Pirates (28)
29. Rangers (29)
30. D-backs (30)

Voters: Alyson Footer, Anthony Castrovince, Jesse Sanchez, Mark Feinsand, Nathalie Alonso, Mike Petriello, Sarah Langs, Andrew Simon, David Venn.